Electrodeposition of nickel



ELECTRUD POSITIGN OF NICKEL David G. Ellis, Parma Heights, Ohio, assignor to The Harshaw Chemical Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Application July 22, 1953, Serial No. 369,722

6 Claims. (Cl. 204-49) I have now discovered that by the use of polyethylene V T Sta es P t nt glycols of high molecular weight in combination with an 7 auxiliary brightener of the aromatic sulfonate type, very excellent, smooth, bright and ductile deposits of nickel are obtained.

So far as I am aware, it has never been realized prior to my invention that polyethylene glycols of high molec-' ular Weight are useful as brightening addition agents in nickel plating. These compounds, being known as wetting agents were tested as anti-pit agents in acid nickel plating and found to be effective to prevent pitting only at such high concentrations as to produce excessive brittleness. I have discovered, however, that when these compounds are used in lower concentrations suitable for producing bright and ductile nickel deposits in cooperation with compounds of the aromatic sulfonate type, and anti-pit agents of the alcohol sulfate type are employed, the deposits are superior in both brightness and freedom from pitting.

The class of addition agents above referred to as aromatic sulfonate type compounds may be defined as compounds of the form ArSO2-, where Ar represents an aromatic radical having not less than 6 nor more than 10 carbon atoms in the aromatic nucleus, such compound being soluble in the plating solution to the extent of at least 0.2 gram per liter. The free valence may be satisfied by various groups, for example OH, and NH, or OM where M can be for example sodium, potassium, nickel, iron, or cobalt. The NH-- group may be NT-Ia or NHSQzAr, Ar having the same significance as before. The aromatic radicals represented by Ar in the above formula may be benzene or naphthalene radicals unsubstituted, or part of the hydrogen may be replaced by substituents such as chlorine, bromine, methyl, and ethyl radicals, etc.

Specific examples are set forth in Table I.

TABLE I 1. Naphthalene l,5-disulfonic acid 2. Naphthalene 2,7-disulfonic acid 3. Diphenyl sulfone disulfonic acids 4. Benzaldehyde monosulfonic acids 5. Benzene monosulfonic acids 6. Toluene monosulfonamide 7. Ortho benzosulfimide, sodium salt 8. Nickel naphthalene disulfonic acids 9 Dibenzene sulfonamide (PhSozNHSOaPh) l The class of compounds referred to above as the high molecular weight polyethylene glycols may be defined as polymeric compounds predominantly .composed of the group CHzOHzO, preferably compounds of the form R-(CH2CH2O)nH, where n is an integer from 10 to 100 and R is a radical selected'from the class consisting of radicals of the form RO and RNH, where R is selected from the class consisting of hydrogen, alkyl radicals having from 1 to 20 carbon atoms, and aryl radicals having from 1 to 20 carbon atoms. In these compounds, replaceable hydrogen may be replaced by alkyl groups having from 15 carbon atoms, to the extent of 20% or less of the number of replaceable hydrogens. Such compounds must be soluble in the bath to the extent of at least .001 gram per liter and preferably are of molecular Weight from 1000 to 6000. From 1% to 50% of the OHzCHzO groups may be replaced by CHzCHzCHzO groups.

Examples are set forth in Table II:

TABLE II Compounds like the foregoing examples where from 1 V to 50% of the CH2CH2O groups are replaced by 0. CsHsSOaNI-ISO2CsH4SO2NHSO2CsHs (bidibenzene sulfonamide) groups.

The addition agents referred to above as alcohol sulfates may be defined as the normal, primary, aliphatic, alcohol sulfates having from 8 to 18 carbon atoms in the molecules, for example:

1. Sodium lauryl sulfate.

2. A mixture of normal, primary, aliphatic, alcohol sulfates derived from cocoanut oil and containing approximately 45% sodium lauryl sulfate, the balance substantially the sodium alcohol sulfates of higher and lower aliphatic alcohols having from 8 to. 18 carbon atoms.

The above described'aclditionagents may be used in nickel plating solutions of the nickel sulfate, nickel chloride, and mixed nickel sulfate-nickel chloride types. The basic solutions, according to the present invention, are as follows:

All sulfate NiCl2.6H2O: 50 to 250gms.,' preferably to 200 gms. Boric acid: 0 to 60 gms., preferably 10 to 40 gms. Wetting agent of the lauryl sulfate type: 0 to 0.5 gm., preferably 0.05 to 0.2 gm. Brightener of the aromatic sulfonate type: 0.2"gm. to

saturation, preferably 05 to 15 gms.

Brightener} of the polyethylene glycol type: .001 to .05

gm, preferably 0.002 to 0.03 gin. H2O to make 1000 cc.

said solution also containing cooperating addition agents capable of imparting brightness to the deposit, one of said NiSO4-7H20I 100 to 400 -a Preferably 200 i 300 addition agents being a compound of the form ArSOz-, i where Ar represents an aromatic radical containing not NiC12-6H20I 10 to 50 Preferably 25 i0 40 g less than 6 nor more than 10 carbon atoms in the aro- Boric acid: 0 to 50 Preferably 15 to 40 matic nucleus, such compound being dissolved in said Wetting agent of the lauryl sulfate yp 0 to solution to the extent of from 0.2 to 15 grams per liter preferably 0.05 to 0.2 gm. and the other of said addition agents being a compound Brightcner of the aromatic sulfonate type: 0.2 gm. to of the form R O(CH CHzO) tH, where n is an intergcr saturation, preferably 0.5 to 15 gms. from 10 to 100 and R is an alkyl radical having from Brightener of the polyethylene glycol type: .001 to .05 1 to 20 carbon atoms, said last mentioned addition agent gm, preferably 0.002 to 0.003 gm. being dissolved in said solution to the extent of from H2O to make 1000 cc. 0.001 to 0.05 gram per liter.

The following table indicates specific. compositions 4. A method of electrodepositing nickel in the form of suitable for use in the practice of the invention: a deposit which is bright as taken from the plating solu- Sulfate-chloride (Watts type) Nickel sulfate heptahydrate Nickel chloride hcxahydrate Boric acid Sodium lauryl sulfate Naphthalene 1,5-disultonie aeitL- saccharine, sodium salt Dibeuzene sulionomldc Bi-dibenzene sulfonamitle HO(CH2OH:'.0)20H- P110 (CHaCHrO HO (CHH30)30H- PhNHwl-ltclliOmtL tion without further treatment, which method comprises .electrolyzing an aqueous acid solution of a nickel electrolyte of the class consisting of nickel sulfate, nickel chloride, and mixtures of nickel sulfate with nickel chloride, said solution also containing cooperating addition agents capable of imparting brightness to the deposit, one of said addition agents being a compound of the form ArSOz, where Ar represents an aromatic radical containing not less than 6 nor more than 10 carbon atoms in the aromatic nucleus, such compound being dissolved in said solution to the extent of from 0.2 to 15 grams per liter and the other of said addition agents being a compound of the form RO(CH2CH2O)HH, where n is an integer from 10 to 100 and R is an aryl radical having Having thus described the invention, what is claimed is: l. A method of electrodepositing nickel in the form of a deposit which is bright as taken from the plating solution without further treatment, which method comprises electrolyzing an aqueous acid solution of a nickel electrolyte of the class consisting of nickel sulfate, nickel chloride, and mixtures of nickel sulfate with nickel chloride, said solution also containing cooperating addition agents capable of imparting brightness to the deposit, one of said addition agents being a compound of the form AISO2, where Ar represents an aromatic radical containing not less than 6 nor more than 10 carbon atoms in the aromatic nucleus, such compound being dissolved in said solution to the extent of at least 0.2 gram per liter and the other of said agents being a compound of the form from 1 to 20 carbon atoms, said last mentioned agent R(CH2CH20)1ZH, where n is an integer from 10 to 100 being dissolved in said solution to the extent of from and R is a radical selected from the class consisting of 0.001 to 0.05 gram per liter. radicals of the form R'O and RNH where R is selected 5. A method of electrodepositing nickel in the form from the class consisting of hydrogen, alkyl radicals of a deposit which is bright as taken from the plating having from 1 to 20 carbon'atoms, and aryl radicals solution without further treatment, which method comhaving from 1 to 20 carbon atoms, said last mentioned prises electrolyzing an aqueous acid solution of a nickel addition agent being dissolved in said solution to the electrolyte of the class consisting of nickel sulfate, nickel extent of from 0.001 to 0.05 gram per liter. chloride, and mixtures of nickel sulfate with nickel 2. A method of electrodepositing nickel in the form of chloride, said solution also containing cooperating addia deposit which is bright as taken from the plating solution agents capable of imparting brightness to the deposit, tion without further treatment, which method comprises one of said addition agents being a compound of the electrolyzing an aqueous acid solution of a nickel electroform ArSO2, where Ar represents an aromatic radical lyte of the class consisting of nickel sulfate, nickel containing not less than 6 nor more than 10 carbon atoms chloride, and mixture of nickel sulfate with nickel chloin the aromatic nucleus, such compound being dissolved ride, said solution also containing cooperating addition in said solution to the extent of from 0.2 to 15 grams per agents bl of imparting brightness. to th d osit, liter and the other of said addition agents being a comone of said addition agents being a compound of the form POlmd 0f the form )11 Whfire n is a ArSOz-, where Ar represents an aromatic radical coninteger from 10 to 100 and R is RNH, R being an alkyl r i i ot le th n 6 n more than 10 carbon atom radical having from 1 to 20 carbon atoms, said last men in the aromatic nucleus, such compound bein dissolved tioned addition agent being dissolved in said solution to in said solution to the extent of from 0.2 to 15 grams the extent of f (1001 M005 gram per liter. per liter and the other of said addition agents being a 6. A method of electrodepositing nickel in the form compound of the form RO(CH2CH2O)1tH, Where n is of a deposit which is bright as taken from the plating an integer from 10 to 100 and R is hydrogen, said last mentioned addition agent being dissolved in said solution prises electrolyzing an aqueous acid solution of a nickel to the extent of from 0.001 to 0.05 gram per liter. electrolyte of the class consisting of nickel sulfate, nickel 3. Amethod of electrodepositing nickel in' the form of chloride, and mixtures of nickel sulfate with nickel a deposit which is bright as taken from the plating soluchloride, said solution also containing cooperating addition without further treatment, which method comprises tion agents capable of imparting brightness to the deelectrolyzing an aqueous acid solution of a nickel electroposit, one of said addition agents being a compound of lyte of the class consisting of nickel sulfate, nickel chlohe f rm AI z-, Whe e r r pres n an aromatic ride, and mixtures of nickel sulfate with nickel chloride, radical containing not less than 6 nor more than 10 solution without further treatment, which method com carbon atoms in the aromatic nucleus, such compound being dissolved in said solution to the extent of from 0.2 to 15 grams per liter and the other of said addition agents being a compound of the form R(CH2CH2O)1H, where n is an integer from 10 to 100 and R is R'NH, R being an aryl radical having from 1 to 20 carbon atoms, said last mentioned addition agent being dissolved in said solution to the extent of from 0.001 to 0.05 gram per liter.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A METHOD OF ELECTRODEPOSITING NICKEL IN THE FORM OF A DEPOSIT WHICH IS BRIGHT AS TAKEN FROM THE PLATING SOLUTION WITHOUT FURTHER TREATMENT, WHICH METHOD COMPRISES ELECTROLYZING AN AQUEOUS ACID SOLUTION OF A NICKEL ELECTROLYTE OF THE CLASS CONSISTING OF NICKEL SULFATE, NICKEL CHLORIDE, AND MIXTURES OF NICKEL SULFATE WITH NICKEL CHLORIDE, SAID SOLUTION ALSO CONTAINING COOPERATING ADDITION AGENTS CAPABLE OF IMPARTING BRIGHTNESS TO THE DEPOSIT, ONE OF SAID ADDITION AGENTS BEING A COMPOUND OF THE FORM ARSO2-, WHERE AR REPRESENTS AN AROMATIC RADICAL CONTAINING NOT LESS THAN 6 NOR MORE THAN 10 CARBON ATOMS IN THE AROMATIC NUCLEUS, SUCH COMPOUND BEING DISSOLVED IN SAID SOLUTION TO THE EXTENT OF AT LEAST 0.2 GRAM PER LITER AND THE OTHER OF SAID AGENTS BEING A COMPOUND OF THE FORM R(CH2CH2O)NH, WHERE N IS AN INTEGER FROM 10 TO 100 AND R IS A RADICAL SELECTED FROM THE CLASS CONSISTING OF RADICALS OF THE FORM R''O AND R''NH WHERE R'' IS SELECTED FROM THE CLASS CONSISTING OF HYDROGEN, ALKYL RADICALS HAVING FROM 1 TO 20 CARBON ATOMS, AND ARYL RADICALS HAVING FROM 1 TO 20 CARBON ATOMS, SAID LAST MENTIONED ADDITION AGENT BEING DISSOLVED IN SAID SOLUTION TO THE EXTENT OF FROM 0.001 TO 0.05 GRAM PER LITER. 